Britain will put slavery survivors at risk of being trafficked again unless it exempts them from fees imposed on immigrants wishing to stay in the country after it leaves the European Union, campaigners said on Monday.

People from European countries who want to remain in Britain after it leaves the EU in March 2019 will need to pay about 65 pounds ($84) for adults and 33 pounds ($43) for children, according to the Home Office (interior ministry).

Britain’s immigration minister, Caroline Nokes, told parliamentarians on Oct. 25 that survivors of modern slavery would not be exempt “unless the victim is a child in local authority care”.

Imposing a Brexit fee on slavery survivors would be “retrograde step” that would undermine their recoveries, said Kate Roberts of the Human Trafficking Foundation, a British charity.

“Charging fees is an extra barrier and hoop for people to jump through who have already been through so much,” Roberts told the Thomson Reuters Foundation.

“Any extra hurdles risk people slipping back underground and into exploitation.”

Nokes’ announcement follows a government decision earlier this year to halve the financial support it gives to victims of modern slavery.

“For us, this is unacceptable in the face of major cuts to the support trafficked people will be getting,” said Caroline Robinson, director of the British charity Focus on Labour Exploitation.

“On top of that, to charge them a fee to stay in the UK flies in the face of the huge priority that the prime minister said she places on the issue of tackling modern slavery.”

Hailed as a global leader in the anti-slavery drive, British Prime Minister Theresa May has made tackling modern slavery a hallmark of her leadership, and the country passed a law in 2015 introducing life sentences for traffickers.

At least 13,000 people across Britain are estimated by the government to be victims of forced labour, sexual exploitation and domestic servitude – but police say the true figure could be in the tens of thousands with slavery operations on the rise.

A spokesman for the Home Office said by email that the government would provide as much as 9 million pounds to community organisations across the country to assist EU citizens who need help applying to stay in Britain.